声波法在三峡工程永久船闸边坡岩体卸荷松弛监测中的应用

Application of sonic technology to monitoring shiplock slope unloading relaxation zone in Three Gorges Project

边坡开挖过程中,一方面由于爆破直接作用使岩体产生松弛破坏:另一方面,由于岩体卸荷作用,应力将重新调整,也将使岩体性状发生改变,最终在边坡一定范围形成与原岩力学性状具有明显差异的卸荷松弛区。声波波速可作为反映岩体力学性状的重要参数,通过声波波速变化揭示船闸高边坡岩体因开挖卸荷及应力调整而产生的卸荷松弛区的规律,从而为边坡设计和支护加固方案提供了重要依据。实践表明,声波监测是一种方便可行的监测方法,不仅能提供岩体力学性质,还能准确划分卸荷松弛层厚度,可为类似工程所采用。

During the excavation of slope,explosion engenders relaxation failure of rock mass;and unloading of ground stress causes the readjusting of stress;the mechanical characteristics of the rock mass changes too.At last,the unloading relaxation zone of which the mechanical characteristics are obviously different to the ones of raw rock mass in certain scope of the slope.Sonic velocity is one of the parameters of mechanical characteristics of the rock mass,so the variation of sonic velocity can post the regularities of the unloading relaxation zone in the shiplock high slope caused by excavation unloading and readjusting of stress;and the regularities can be important gist for the design and reinforcing of the slope.Testing results prove that sonic technology is convenient and feasible.It not only provides the mechanical characteristics of the rock mass,but also make certain the thickness of unloading relaxation zone.It can be used for similar projects.